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Question 1
Correct
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Renin is produced by which of the following:
Your Answer: Granular cells in the wall of the afferent arteriole
Explanation:Juxtaglomerular cells are specialised smooth muscle cells mainly in the walls of the afferent arterioles (and some in the efferent arterioles) which synthesise renin.
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This question is part of the following fields:
- Physiology
- Renal
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Question 2
Incorrect
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A 28-year-old asthmatic patient is seen in the Emergency Department following an acute exacerbation. His symptoms start to improve when your consultant gives him a high dose of IV aminophylline.Which of the following is correct mechanism of action of aminophylline ?
Your Answer: Muscarinic receptor antagonism
Correct Answer: Inhibition of phosphodiesterase
Explanation:Aminophylline has the following properties:Phosphodiesterase inhibitor that increases intracellular cAMP and relaxes smooth muscle in the bronchial airways and pulmonary blood vessels.Mast cell stabilization is achieved by using a non-selective adenosine receptor antagonist.
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This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 3
Incorrect
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Which of the following best describes a natural killer cell:
Your Answer: A large phagocyte that is part of the innate immune system.
Correct Answer: A large granular lymphocyte that kills by inducing target cell apoptosis.
Explanation:Natural killer (NK) cells are cytotoxic CD8 positive cells that lack the T-cell receptor. They are large cells with cytoplasmic granules. NK cells are designed to kill target cells that have a low level of expression of HLA class I molecules, such as may occur during viral infection or on a malignant cell. NK cells do this by displaying several receptors for HLA molecules on their surface. When HLA is expressed on the target cell these deliver an inhibitory signal into the NK cell. When HLA molecules are absent on the target cell this inhibitory signal is lost and the NK cell can then kill its target. In addition, NK cells display antibody-dependent cell-mediated cytotoxicity. In this, antibody binds to antigen on the surface of the target cell and then NK cells bind to the Fc portion of the bound antibody and kill the target cell.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 4
Incorrect
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An 11-year-old girl presents with a 5-day history of persistent fever despite regular paracetamol, throbbing left ear pain, ear discharge and deafness. Her parents have observed that she is not her usual self, not eating well, and has been lethargic. On examination there is a tender swelling in the post auricular region on the left hand side.What is the most likely causative organism?
Your Answer: Pasturella multocida
Correct Answer: Streptococcus pneumonia
Explanation:Acute mastoiditis is a complication (rare) of acute otitis media (AOM) and the commonest causative organism is Streptococcus pneumoniae.Generally, acute mastoiditis presents with:PyrexiaRecent history of AOMMastoid swelling and erythemaOtalgiaOtorrhoea and perforation of tympanic membranePost-auricular painProtrusion of the ears
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 5
Correct
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Which of the following is required for vitamin B12 absorption:
Your Answer: Intrinsic factor
Explanation:Intrinsic factor is essential for the absorption of the small amounts of vitamin B12 normally present in the diet from the terminal ileum. The parietal cells of the stomach produce intrinsic factor, and following a gastrectomy, the absorption of vitamin B12 will be markedly reduced, and a deficiency state will exist.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 6
Incorrect
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Approximately what proportion of lymphocytes are B-cells:
Your Answer:
Correct Answer: 0.2
Explanation:B-cells (20% of lymphocytes) mature in the bone marrow and circulate in the peripheral blood until they undergo recognition of antigen. B-cell immunoglobulin molecules synthesised in the cell are exported and bound to the surface membrane to become the B-cell receptor (BCR) which can recognise and bind to a specific antigen (either free or presented by APCs). The BCR is also important for antigen internalisation, processing and presentation to T helper cells. Most antibody responses require help from antigen-specific T helper cells (although some antigens such as polysaccharide can lead to T-cell independent B-cell antibody production). When the B-cell is activated, the receptor itself is secreted as free soluble immunoglobulin and the B-cell matures into a memory B-cell or a plasma cell (a B-cell in its high-rate immunoglobulin secreting state). Plasma cells are non-motile and are found predominantly in the bone marrow or spleen. Most plasma cells are short-lived (1 – 2 weeks) but some may survive much longer. A proportion of B-cells persist as memory cells, whose increased number and rapid response underlies the augmented secondary response of the adaptive immune system.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 7
Incorrect
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A patient who is taking ramipril for high blood pressure complains of a dry persistent cough. What is the mechanism of cough in ACE inhibitor therapy:
Your Answer:
Correct Answer: Decreased bradykinin breakdown
Explanation:Blocking ACE also diminishes the breakdown of the potent vasodilator bradykinin which is the cause of the persistent dry cough. Angiotensin-II receptor blockers do not have this effect, therefore they are useful alternative for patients who have to discontinue an ACE inhibitor because of persistent cough.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 8
Incorrect
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A 64-year-old man presents with an acute episode of gout. He has a history of chronic heart failure and hypertension. His current medications include ramipril and furosemide.Which of the following statements regarding the treatment of gout is true? Select ONE answer only.
Your Answer:
Correct Answer: Colchicine has a role in prophylactic treatment
Explanation:In the absence of any contra-indications, high-dose NSAIDs are the first-line treatment for acute gout. Naproxen 750 mg as a stat dose followed by 250 mg TDS is a commonly used and effective regime.Aspirin should not be used in gout as it reduces the urinary clearance of urate and interferes with the action of uricosuric agents. Naproxen, Diclofenac or Indomethacin are more appropriate choices.Allopurinol is used prophylactically, preventing future attacks by reducing serum uric acid levels. It should not be started in the acute phase as it increases the severity and duration of symptoms.Colchicine acts on the neutrophils, binding to tubulin to prevent neutrophil migration into the joint. It is as effective as NSAIDs in relieving acute attacks. It also has a role in prophylactic treatment if Allopurinol is not tolerated.NSAIDs are contra-indicated in heart failure as they can cause fluid retention and congestive cardiac failure. Colchicine is the preferred treatment in patients with heart failure or those who are intolerant of NSAIDs.
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This question is part of the following fields:
- Musculoskeletal Pharmacology
- Pharmacology
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Question 9
Incorrect
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A 55-year-old woman with a known history of bronchiectasis has lung function testing carried out and is found to have significant airways obstruction.Which of the following lung volumes or capacities is LEAST likely to be decreased in this case? Select ONE answer only.
Your Answer:
Correct Answer: Functional residual capacity
Explanation:Obstructive lung disorders are characterised by airway obstruction. Many obstructive diseases of the lung result from narrowing of the smaller bronchi and larger bronchioles, often because of excessive contraction of the smooth muscle itself.In obstructive lung disease, FEV1is reduced to <80% of normal and FVC is usually reduced but to a lesser extent than FEV1. The FEV1/FVC ratio is reduced to 80% in the presence of symptomsModerate airflow obstruction = FEV1of 50-79%Severe airflow obstruction = FEV1of 30-49%Very severe airflow obstruction = FEV1<30%.
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This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 10
Incorrect
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Injury to which nerve can lead to weakness or paralysis of the brachialis muscle?
Your Answer:
Correct Answer: The musculocutaneous nerve
Explanation:The brachialis muscle is a prime flexor of the forearm at the elbow joint. It is fusiform in shape and located in the anterior (flexor) compartment of the arm, deep to the biceps brachii. The brachialis is a broad muscle, with its broadest part located in the middle rather than at either of its extremities. It is sometimes divided into two parts, and may fuse with the fibres of the biceps brachii, coracobrachialis, or pronator teres muscles. It also functions to form part of the floor of the cubital fossa.The brachialis is primarily supplied by the musculocutaneous nerve (C5, C6). In addition, a small lateral portion of the muscle is innervated by the radial nerve (C7).
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This question is part of the following fields:
- Anatomy
- Upper Limb
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SESSION STATS - PERFORMANCE PER SPECIALTY
